Molybdenum compounds having a thiocubane structure are produced by a variety of methods. For example, T. Shibahara et al, J. Am. Chem. Soc., 106. pp. 789-791 (1984) discusses a method for making the [Mo.sub.4 S.sub.4 (edta).sub.2 ]3- ion containing species by reacting a water soluble Mo(V) dimer in HCl. P. Kathirgamanathan et al, J. Chem. Soc., Chem. Commun., pp. 953-954 (1985), describes electrochemically reducing a Na.sub.2 [Mo(V).sub.2 S.sub.2 O.sub.2 (cysteine).sub.2 ].3H.sub.2 O in HCl to form (Me.sub.4 N).sub.5 [Mo.sub.3 S.sub.4 (NCS).sub.9 ] and the tetramer (Me.sub.4 N).sub.7 [Mo.sub.4 S.sub.4 (NCS).sub.12 ]. P. Kathirgamanathan et al, J. Chem. Soc., Chem. Commun., pp. 1437-1439 (1985), describes preparing mixtures of (Me.sub.4 N).sub.5 [Mo.sub.3 X.sub.4 (NCS).sub.9 ]and (Me.sub.4 N).sub.7 [Mo.sub.4 X.sub.4 (NCS).sub.12 ] compounds, where X is sulfur or oxygen. More recently, in U.S. Pat. No. 4,990,271 there is described a method for making thiocubane Mo compounds having the formula Mo.sub.4 S.sub.4 (ROCS.sub.2).sub.2 by reacting molybdenum hexacarbonyl, Mo(CO).sub.6, with a xanthogen disulfide.
Notwithstanding the plethora of methods for preparing molybdenum containing thiocubane type compounds, there remains a need for a preparative method that is more simple and less expensive.
It is, therefore, an object of the present invention to provide an improved method for forming thiocubane Mo compounds of the general formula Mo.sub.4 S.sub.4 L.sub.6, where L is a dithioacid ligand.